JP2002260724A - High-temperature sodium secondary battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-temperature sodium secondary battery module suitable for use in a power storage system or an electric automobile. SOLUTION: With the high-temperature secondary battery module with a plurality of high-temperature sodium batteries electrically connected and contained inside a warm vessel, an outer wall of the warm vessel constituting the module is of stainless steel or SUS plate, characteristically with the thickness of not less than 1.6 mm or not less than 2.3 mm. Further, it is desired to store keeping the longer side of the high-temperature sodium secondary battery sideways inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature sodium secondary battery module suitable for use in an electric power storage device and an electric vehicle.

[0002]

2. Description of the Related Art A negative electrode chamber is filled with liquid sodium and a positive electrode chamber is filled with a positive electrode active material such as sulfur, sodium polysulfide, selenium, tellurium, and metal chloride. High-temperature sodium secondary batteries with a structure separated by a solid electrolyte bag tube made of beta-alumina ceramics are attracting attention because of their long life and large energy density, and are suitable for load leveling, which stores nighttime power and uses it during the day. In order to expand the use of batteries, the difference in electricity rates between the day and night will cover the equipment costs of the battery system, thereby encouraging the application of power storage devices to the private sector. It is important to reduce the cost of the battery system.

The operating temperature of this battery is as high as 100 ° C. or more, which is higher than the melting point of sodium.
As seen in, for example, U.S. Pat. No. 94128, the battery is usually used as a module in which a battery is housed in a heat insulating container such as a vacuum heat insulating container.

[0004] As disclosed in Japanese Patent Application Laid-Open No. 11-40190, there is a method in which a heat-insulating container containing a battery is housed in a fire-resistant container such as a cubicle to take measures against the Fire Service Law.

[0005]

However, the above prior art has the following problems.

[0006] The high-temperature sodium secondary battery module uses sodium, which is a dangerous substance under the Fire Services Act,
There are legal restrictions on the location and building where the battery module is installed, and addressing this problem is one of the points for expanding the use of batteries.

That is, the building in which the high-temperature sodium secondary battery is installed must have a fire-resistant structure, or an open space of 3 m or more should be provided around the battery equipment, and a fire door must be provided when the building has an entrance. There is a problem that it is difficult to reduce the cost of the battery system in the module having the conventional structure described in Japanese Patent Application Laid-Open No. 10-294128 or the like because of the construction cost of the installed building and the cost of the necessary vacant space. Was.

In the battery module described in Japanese Patent Application Laid-Open No. H11-40190, it is possible to take measures against the Fire Services Act by storing a heat-insulating container containing a battery in a fire-resistant container such as a cubicle. In this case, batteries are housed in a heat-insulating container and a fire-resistant container, which is not enough to reduce the cost of the system.

Further, in order to reduce the module cost per kW or kWh, it is desirable to increase the size of the unit cell which accounts for most of the cost, increase the capacity of the unit cell, and reduce the number of cells. However, when a bag-shaped tubular solid electrolyte is used upright, as is generally done, the length of the solid electrolyte bag tube is generally larger than the diameter, and the height of the battery is larger than the width. Is also larger,
As the capacity increases, the height of the battery increases, and the height of the thermal insulation container also increases.Therefore, as in the case of installing a high-temperature sodium secondary battery in an electric vehicle or a small building, the height of the installation space is limited. In some cases, there has been a problem that installation of the module becomes difficult. Furthermore, when a high-temperature sodium secondary battery module is installed in a building, the weight limit is about 500 to 1000 kg per 1 m2 unless special reinforcement work is performed even in an underground installation. Although there is a weight limit per area, for example, it is necessary to make it about 300 to 500 kg or less per 1 m2, the module weight per unit area when a large battery is erected tends to be larger than this, making it difficult to install indoors There was also the problem of becoming. In addition, even when the battery is upright, it is possible to reduce the weight per unit area by reducing the battery filling density in the module,
In this case, there is a new problem that the area and volume of the module increase and the energy density decreases.

When the capacity of a unit cell is increased to reduce the cost of the module, it is necessary to increase the height and / or width of the solid electrolyte bag tube. There is a problem that the concentration distribution and composition distribution of the active material tend to be formed by gravity in the vertical direction in the room, and as a result, an electromotive force distribution is generated in the battery, a circulating current flows, and the efficiency of the battery is reduced. On the other hand, it is possible to increase the width of the solid electrolyte bag tube without changing the height, but in this case, the ratio between the volume and the surface area of the solid electrolyte bag tube becomes large, and the solid electrolyte bag tube is filled. In order to cause the active material to react within a predetermined time, it is necessary to increase the current density during operation, and there is a problem that the efficiency of the battery is reduced due to the influence of the internal resistance. When the battery efficiency decreases, the battery output decreases. As a result, the required number of batteries per kW or kWh increases, and the cost of the module increases.

A first object of the present invention is to provide a high-temperature sodium secondary battery module that has a simple structure and high fire resistance of the module, so that the cost of the battery system can be easily reduced.

A second object of the present invention is to provide a high-temperature sodium secondary battery module in which the height of the module can be reduced without lowering the energy density, and as a result, the module can be easily installed. It is in.

A third object of the present invention is to provide a high battery efficiency,
An object of the present invention is to provide a high-temperature sodium secondary battery module that can reduce the module cost per unit output and, as a result, can easily realize a low cost battery system.

[0014]

(1) In order to achieve the first object, the present invention relates to a high-temperature sodium secondary battery in which a plurality of high-temperature sodium secondary batteries are electrically connected and housed inside a heat insulating container. In the module, it is assumed that an outer wall of the heat retaining container constituting the module is made of a steel plate or a SUS plate, and has a thickness in a range of 1.6 mm to 10.0 mm.

The outer wall of the heat insulating container constituting the heat insulating container is made of a steel plate having a thickness of 1.6 mm to 10.0 mm or S.
By using the US plate, the battery module of the present invention does not need to be stored in a fire-resistant building or cubicle, and has a simple structure and high fire resistance of the module. As a result, the cost of the battery system can be easily reduced. Can be realized.

Here, in order to secure fire resistance, when the module is installed in a building, the thickness of the outer wall is set to 1.6.
mm or more. Further, in order to make the weight of the steel plate or the SUS plate as low as possible and to facilitate the movement, and to reduce the manufacturing cost, it is preferable that the thickness of the steel plate or the SUS plate on the outer wall is 10 mm or less.

(2) In the above (1), preferably,
The thickness of the outer wall is 2.3 mm or more.

As described above, in order to ensure fire resistance, when the module is installed in a building, the thickness of the outer wall must be 1.6 mm or more, but the module is installed outside the building. In this case, the thickness of the outer wall is preferably set to 2.3 mm or more.

(3) In the above (1) or (2), the inside of the outer wall is filled with a heat insulating material, or the space inside the outer wall is evacuated or depressurized, so that the inside is reduced. It is desirable that the high-temperature sodium secondary battery stored in the battery be kept warm.

(4) In the above (1), (2) or (3), it is particularly preferable that the upper surface and the side surface of the outer wall are hermetically sealed.

(5) In order to achieve the second and third objects, the present invention provides the above-mentioned (1) to (4), wherein the longitudinal direction of the high-temperature sodium secondary battery is set horizontally or obliquely. It shall be stored lying down.

By storing the high-temperature sodium secondary battery horizontally or diagonally, the height of the module can be reduced without lowering the energy density. As a result, the module can be installed. Becomes easier. Further, the battery efficiency is high, and the module cost per unit output can be reduced. As a result, the cost of the battery system can be easily reduced.

(6) In the above (1) to (5), a plurality of the high-temperature sodium secondary batteries can be stacked and housed in the vertical direction.

(7) In the above (6), preferably, a column and a shelf are provided in the module, and the high-temperature sodium secondary battery is supported by the column and the shelf.

(8) In the above (1) to (6), it is preferable that the side surface of the high-temperature sodium secondary battery has a rectangular parallelepiped shape.

(9) Further, in the above (1) to (6), preferably, all the batteries housed in the module are connected in series.

(10) In the above (6), a battery is formed by serially connecting batteries arranged vertically in the module to form a string, and connecting the batteries located at the ends of the string in parallel. It is desirable to form blocks.

(11) Further, in the above (6), a string is formed by serially connecting the batteries arranged in the module in the lateral direction, and a battery is formed by connecting the batteries located at the end of the string in parallel. Blocks may be formed.

(12) The above (10) or (11)
In the above, the battery blocks may be connected in series or / and in parallel.

(13) In order to achieve the above-mentioned second and third objects, the present invention provides a method in which a plurality of high-temperature sodium secondary batteries are laid horizontally or diagonally, and the series connection or series connection is performed. In the high-temperature sodium secondary battery module connected in parallel and stored in the module, the longitudinal ends of the plurality of high-temperature sodium secondary batteries connected in series are alternately arranged in opposite directions, and the space between the positive electrode / negative electrode of the adjacent batteries is changed. Electrical connection shall be made.

By storing the high-temperature sodium secondary battery in such a manner that the longitudinal direction of the battery is laid horizontally or obliquely, the height of the module can be reduced without lowering the energy density. Becomes easier. Further, the battery efficiency is high, and the module cost per unit output can be reduced. As a result, the cost of the battery system can be easily reduced.

Further, the longitudinal ends of a plurality of high temperature sodium secondary batteries connected in series are alternately arranged in opposite directions,
By electrically connecting the positive electrode / negative electrode of the adjacent batteries, the bus bar used for the connection can be shortened. As a result, the battery structure and the connection structure are simplified, and the cost of the module can be easily reduced.

(14) Further, in order to achieve the second and third objects, according to the present invention, a plurality of high-temperature sodium secondary batteries are laid horizontally or obliquely and the high-temperature sodium secondary batteries are stored in a module. In the sodium secondary battery module, the side surface of the high-temperature sodium secondary battery has a rectangular parallelepiped shape.

By storing the high-temperature sodium secondary battery horizontally or diagonally in this manner, the height of the module can be reduced without lowering the energy density. As a result, the module can be installed. Becomes easier. Further, the battery efficiency is high, and the module cost per unit output can be reduced. As a result, the cost of the battery system can be easily reduced.

Further, by making the side surface of the high-temperature sodium secondary battery have a rectangular parallelepiped shape, the mechanical stability when the battery is placed horizontally is improved. Furthermore, since the average distance between the high-temperature sodium secondary battery and the member of the heat retaining container constituting the module and the average distance between the batteries can be made smaller than in the case where a cylindrical battery is used, the volume in a module having the same volume is reduced. A single cell having a large capacity can be accommodated, or the internal volume of the module can be reduced for a single cell having the same volume, and as a result, the energy density of the module can be improved.

(15) In the above (14), it is preferable that a plurality of the high temperature sodium secondary batteries are stacked in the vertical direction and stored.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing a structure of a high temperature sodium secondary battery module according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.

In FIGS. 1 and 2, reference numeral 1 denotes an outer wall of a heat insulating container 30 constituting a module, which has a thickness of 1.6 mm or more, preferably 2.3 mm in consideration of fire resistance.
It is made of a steel plate or SUS plate of 10 mm or less. In addition, the upper surface 11 and the side surface 12 of the outer wall 1 are air-tightly joined.

Reference numeral 2 denotes an inner wall of the heat retaining container 30. In this figure, the upper surface 21 covers the side surface 22 and serves as a lid. Reference numeral 3 denotes a heat insulating material filled between the outer wall 1 and the inner wall 2. By appropriately selecting the thickness, the temperature of the high-temperature sodium secondary battery 10 installed inside is kept in an appropriate range. . It is desirable that the heat insulating material be made of a non-combustible material such as rock wool in order to improve the fire resistance of the module. Reference numeral 4 denotes a bottom plate that supports the entire module, and is connected to the outer wall 1 via bolts 5.
It is fixed to the floor or the ground of the building by these bolts. This bottom plate also has a thickness of 1.6 mm or 2.3 mm.
It is desirable that it is a steel plate or a SUS plate of not less than 10 mm and not more than 10 mm. Further, the heat insulating material 3 is also filled on the bottom plate 4, and the outer wall 1, the inner wall 2, the bottom plate 4 and the heat insulating material 3 constitute a heat insulating container 30.

Reference numerals 6 and 7 denote columns and shelves, respectively, which support the weight of the high-temperature sodium secondary battery 10 housed in the module. The lower part of the pillar 6 is fixed to the bottom plate 4. Reference numeral 8 denotes a heater provided in the heat insulating container, which serves to raise the temperature from room temperature, to maintain the temperature when the battery operation is stopped, and to control the temperature in the heat insulating container during the battery operation. Reference numeral 9 denotes an insulating material such as a mica plate, which plays a role of electrical insulation between the high-temperature sodium secondary batteries and between the batteries and the inner wall 2, the pillar 6, and the shelf 7.

Reference numeral 10 denotes a high-temperature sodium secondary battery, which is arranged in a horizontal direction and a vertical direction in a heat insulating container. Here, although not shown, the high-temperature sodium secondary battery is composed of a negative electrode chamber containing liquid sodium, a positive electrode chamber containing a positive electrode active material, the negative electrode chamber, and a solid electrolyte separated from the positive electrode chamber. ing. In FIG. 1, the high-temperature sodium secondary battery has an outer container having a cylindrical shape. Although not shown, a solid electrolyte bag tube having a bottomed tubular shape and a length larger than the diameter is accommodated therein. The battery is placed in a heat insulating container with the tube laid horizontally or obliquely, with the longitudinal direction of the battery being horizontal or oblique. Alternatively, the batteries can be arranged upright. Instead of the solid electrolyte bag tube, flat high-temperature sodium secondary batteries using a flat solid electrolyte can be stacked and placed in the heat insulation container. Furthermore, it is also possible to make the outer surface of the battery such as a battery container into a rectangular parallelepiped shape to improve the packing density in the battery module.

Reference numeral 13 denotes a bus bar for connecting the batteries, and 1
Reference numeral 4 denotes a bus bar for connecting the battery and an external circuit. The gap 17 between the bus bar 14 and the bottom plate 4 is desirably filled with a non-combustible material such as rock wool, mortar, fireproof seal material, fireproof putty, and the like. Although not shown, an electric wiring for measuring the temperature and battery voltage inside the module may be passed through the gap provided in the bottom plate 4 together with the bus bar 14.

In FIG. 1 and FIG. 2, a negative electrode 101 and a positive electrode 102 are provided on one side in the longitudinal direction of the battery, and a plurality of batteries connected in series are arranged alternately in the longitudinal direction in opposite directions. A string is formed by connecting the negative electrode 101 and the positive electrode 102 of the vertically adjacent batteries in series to form a string, and the negative electrodes and the positive electrodes between the uppermost and lowermost adjacent batteries constituting the string end are connected in parallel. By forming a battery block in which a plurality of strings are connected in parallel and connecting the uppermost batteries constituting the ends of each battery block in series, the plurality of batteries included in the heat insulation container are directly connected. The modules are connected in parallel. In some cases, a module can be configured by connecting the battery blocks in series / parallel.

Further, reference numeral 15 denotes insulating particles such as dry sand filled between the batteries or between the batteries and the heat insulation container. In addition to providing electrical insulation, if the battery is damaged and liquid sodium or a liquid cathode active material leaks from the battery, the sodium or cathode active material is retained between the insulating particles and prevented from moving. This has the effect of preventing the transmission of damage to the battery and increasing the safety of the module.
When the high-temperature sodium secondary battery 10 is a sodium-sulfur battery, sulfur or sodium polysulfide is used as the positive electrode active material. On the other hand, in a high-temperature sodium secondary battery other than the sodium-sulfur battery, sulfur is used as the positive electrode active material. ,
Elements of selenium and tellurium, chlorides thereof, and metal chlorides (metals such as Al, Ni, and Fe) are used.

Reference numeral 16 denotes a fixing jig for fixing the module to a wall of a building or the like. The module is fixed by the bolts 5 provided on the bottom plate 4 and the fixing jig 16, so that the module can withstand earthquake resistance. To increase the safety of the module. Further, although not shown, it is desirable to protect the module with a lightning rod to increase the lightning resistance of the module. When the module is arranged indoors or when the thickness of the outer wall 1 is 3.2 mm or more, the lightning rod can be omitted.

In the high-temperature sodium secondary battery module of the present invention, since the outer wall 1 constitutes a heat-insulating container 30 having a fire-resistant structure, it is not necessary to store it in a fire-resistant structure or a cubicle. The structure is simplified and the cost can be reduced as compared with a structure in which a heat insulating container containing a battery is installed in a fireproof structure container such as a cubicle. Also, the outer wall 1 is made of a steel plate or a SUS plate,
Since it has a sufficient thickness as a fire-resistant wall, storing high-temperature sodium rechargeable batteries in this module can ensure fire safety and can be used by storing the module in a normal building. Can be
When the module is installed outside, there is an advantage that it is not necessary to provide an open space around the module, and the use range of the module can be expanded. In addition, in order to ensure fire resistance, the thickness of the steel plate or SUS plate of the outer wall 1 is set to 1.6 mm or more when the module is installed in the building, and the outer wall 1 is set when the module is installed outside the building. It is necessary to make the thickness of the steel plate or SUS plate of 2.3 mm or more. On the other hand, the thickness of the steel plate or the SUS plate of the outer wall 1 is preferably set to 10 mm or less in order to make the weight of the steel plate or the SUS plate as low as possible and facilitate the movement, and to suppress the manufacturing cost.

In FIGS. 1 and 2, since the solid electrolyte bag tube having a length larger than the diameter is placed horizontally and the longitudinal direction of the battery is set horizontally or obliquely, the battery is placed in the vertical direction. The height becomes small, and the concentration distribution and composition distribution of the positive electrode active material due to gravity become difficult to be formed in the vertical direction of the high-temperature sodium secondary battery, circulating current due to the electromotive force distribution in the battery is suppressed, and the battery efficiency is reduced. improves. Furthermore, in the solid electrolyte bag tube, by making the length larger than the diameter, the ratio between the internal volume and the surface area of the solid electrolyte bag tube becomes relatively small, and the diameter is about the same as the length or the diameter is larger. There is also an advantage that the current density per surface area of the solid electrolyte bag tube can be reduced during operation as compared with the case of using the solid electrolyte bag tube, so that the battery efficiency is improved. As a result, the efficiency of the module can be improved, the output of the unit cell can be increased, and the number of stored batteries can be reduced, so that there is an advantage that the module cost per unit output can be reduced. Here, when the longitudinal direction of the battery is inclined, the longitudinal direction of the battery, that is, the angle between the axial direction of the solid electrolyte bag tube and the horizontal direction is desirably ± 45 ° or less.

This horizontal effect is particularly remarkable when the length of the solid electrolyte bag tube is increased in order to increase the size of the unit cell, and it is possible to achieve both the increase in the size of the battery and the improvement in efficiency. As a result, the cost of the module can be reduced by reducing the number of batteries per unit output or unit capacity.

Further, since the longitudinal direction of the battery is laid horizontally, the height of the battery can be reduced even if the capacity of the unit cell is increased. As a result, the height of the module for storing the battery can be reduced, and The module can be easily installed even when the installation space is limited in height, such as when a high-temperature sodium secondary battery is installed in a small building or an electric vehicle.

For these purposes, it is desirable to arrange the batteries so that the longitudinal direction of the batteries is laid horizontally rather than obliquely. As a result, the height of the batteries in the vertical direction is reduced.
It is easy to improve the efficiency of batteries and modules and to reduce the height of modules. In addition, when installing a high-temperature sodium secondary battery module in a building, the number of vertically stacked batteries can be reduced in the vertical direction to reduce the weight of the module per unit area. There is also an advantage that rooftop installation can be easily performed. On the other hand, if the number of stacked batteries in the vertical direction is increased, there is an advantage that the installation area of the module can be reduced correspondingly and the module can be installed even in a small area.

As described above, in the present embodiment,
It is possible to realize a high-temperature sodium secondary battery module suitable for practical use, for example, improving the degree of freedom of the installation space and the area of the module, and achieving both low cost and high efficiency of the module.

Further, a plurality of high temperature sodium secondary batteries 1
0 lays the longitudinal direction horizontally, horizontal direction (horizontal direction)
The batteries are arranged in the vertical direction, so that it is possible to increase both the size of the battery and improve the efficiency. As a result, the number of batteries per unit output or unit capacity is reduced, thereby further reducing the cost of the module. Is possible.

Further, since the upper surface 11 and the side surface 12 of the outer wall 1 are air-tightly connected, when water is discharged by fire extinguishing during a fire or when the basement is flooded when installed in a basement of a building. In such a case, the risk of water entering the module can be reduced, and the safety of the module is improved. 1 and 2, the lower part of the module is not airtight and air and gas can enter and exit in order to cope with a pressure change of gas such as internal air due to a temperature change in the module. However, even when the module is flooded, since the inside is filled with 1 atm of air or possibly an inert gas, the amount of intrusion of water is small, and since the internal temperature of the module is high, When water enters the module, it may become water vapor and increase the internal gas pressure, preventing further water from entering the module. There is no risk of damage to the battery even if it is submerged at a low temperature. In order to increase the waterproof effect of the module, the high-temperature sodium secondary battery 1 filled in the module must be used.
It is desirable that the distance between the lowermost part of 0 and the bottom of the bottom plate 4 is 10 cm or more.

FIGS. 3, 4 and 5 show the structure of a high-temperature sodium secondary battery module according to another embodiment of the present invention, and the components denoted by the same reference numerals as those in FIGS. 1 and 2 are the same. Indicates the content.

Also in FIG. 3, since a plurality of high temperature sodium secondary batteries 10A are arranged in a horizontal direction (horizontal direction) and a vertical direction with the longitudinal direction laid down horizontally, as in FIGS. It is possible to achieve both an increase in the size of the battery and an improvement in efficiency, and as a result, it is possible to reduce the cost of the module by reducing the number of batteries per unit output or unit capacity.

In FIG. 3, adjacent batteries arranged in the horizontal direction are connected in series to form a string, and batteries at both ends of each string are connected in parallel to form a battery block. Make up. further,
As shown in the figure, most of the outer container side surface of the high-temperature sodium secondary battery is a rectangular parallelepiped battery,
As a result, the mechanical stability when the battery is placed horizontally is improved. Furthermore, the average interval between the high temperature sodium secondary battery 10A and the inner wall 2, the pillar 6, and the shelf 7 of the heat retaining container 30 constituting the module and the average interval between the batteries can be made smaller than the case where a cylindrical battery is used. Therefore, a cell having a large capacity can be accommodated in a module having the same volume as in FIGS. 1 and 2, and the internal volume of the module can be reduced in a cell having the same volume (not shown). There is an advantage that the energy density of the module is improved. Note that this effect is particularly remarkable when a plurality of batteries are stacked and filled in the vertical direction along with the horizontal direction,
The average spacing between batteries can be reduced both in the horizontal direction and in the vertical direction, and the horizontally placed batteries can be easily stored with high mechanical stability, resulting in a highly practical high-temperature sodium secondary battery module. You. Further, as described above, the effect of laying the battery sideways can provide advantages of improved module efficiency and reduced cost.

Here, in FIGS. 1, 2 and 3,
The plurality of high temperature sodium secondary batteries 10 connected in series are laid horizontally or obliquely, and the longitudinal directions of the batteries are alternately arranged in opposite directions, and these batteries are connected by a bus bar 13. . Generally, in a high-temperature sodium secondary battery, the battery structure can be simplified by providing the negative electrode 101 and the positive electrode 102 of the battery at both ends in the longitudinal direction of the battery as shown in FIG.
Further, by alternately reversing the longitudinal direction between the batteries connected in series and bringing the positive terminal and the negative terminal between the batteries closer to each other, the bus bar used for connection can be shortened. As a result, the battery structure and the connection structure are simplified, and the cost of the module can be easily reduced.

In FIG. 4 as well, the high-temperature sodium secondary battery 10B is arranged so that the longitudinal direction is laid horizontally, and a plurality of batteries are adjacent to each other in the horizontal direction with an insulating material 9 interposed therebetween.
The batteries are arranged so as to be closely packed also in the vertical direction. As a result, the packing density of the batteries is increased, and the energy density of the module is improved. In addition, the lowermost battery is supported by columns 6B and shelves 7B provided at the lower part, and the weight of the battery thereon is supported by the rigidity of the external container of each battery. Further, in the battery 10B of FIG. 4, a negative electrode 101 and a positive electrode 102 are provided on one side in the longitudinal direction of the battery, and the negative electrode / positive electrode of each battery is connected by a bus bar 13, so that all the batteries included in the module are included. Are connected in series. Further, the upper surface 11 and the side surface 12 of the outer wall 1 and the upper surface 21, the side surface 22 and the bottom surface 23 of the inner wall 2 constituting the heat retaining container 30 are airtightly connected to each other, and the space 31 inside the outer wall is evacuated or depressurized. The insulation of the thermal insulation container has been enhanced, and the module has been downsized. In addition, in FIG. 4, the heat insulating material 3 is filled between the bottom plate 4 and the shelf 7B constituting the lower part of the heat retaining container, but this part can be vacuum-insulated in some cases.

In FIG. 5, a plurality of high-temperature sodium secondary batteries 10B are arranged in a horizontal direction and a vertical direction with the longitudinal direction thereof set upright. In FIG. 5, a negative electrode 101 is provided on the upper part of the battery, and a positive electrode 102 is provided on the side part.
All batteries in the module are connected in series.

Here, when the cells are stacked in the vertical direction and stored in the heat insulating container as in the module structure of the present invention, the cells are disposed between the upper and lower cells due to the influence of gas convection such as air in the heat insulating container. A temperature difference causes a difference in battery resistance between batteries installed above and below. When batteries having different battery resistances are connected in parallel, a circulating current flows between the batteries, and the efficiency of the module decreases. Furthermore, a current imbalance occurs between the batteries, and the battery in which a larger current flows than the other parallel batteries reaches the charge / discharge limit earlier, and the module reaches the operation limit with the capacity of the other parallel batteries remaining. There is a problem that the capacity of the module is reduced. This problem can be dealt with to some extent by making the upper density of the heater 8 smaller than that of the lower part, but it is difficult to reduce the temperature difference between the upper and lower batteries when the heater is hardly operated such as during discharging. In addition, when the longitudinal direction of the battery is laid horizontally or obliquely as shown in FIGS. 1, 2, 3, and 4, the height of each battery in the vertical direction is changed as shown in FIG. Since the height of the module is smaller than that in the case of standing upright, if the height of the module is the same, the temperature difference between the uppermost battery and the lowermost battery tends to be large, and the temperature difference between the upper and lower batteries is a particularly serious problem. On the other hand, in the case where upright batteries are stored in a horizontal direction in the thermal insulation container without being stacked vertically as in the conventional module structure, the vertical temperature difference in the thermal insulation container causes the vertical Even if there is a temperature difference in the direction, the temperature difference between the batteries is small, so the problem of the temperature difference between the batteries is unlikely to occur. It is desirable to take appropriate countermeasures when storing in a stack.

In order to solve this problem, in the structures shown in FIGS. 4 and 5, since all the batteries constituting the module are connected in series, there is a temperature gradient in the heat retaining container constituting the module, and there is a gap between the batteries. Even if there is a difference in battery resistance, there is no problem that a circulating current flows between the batteries in the module, there is no problem of current imbalance between the batteries, and there is an advantage that the efficiency and capacity of the module are kept high. When all the batteries are connected in series, not only the temperature distribution in the vertical direction of the thermal insulation container but also in the case of a temperature distribution in the horizontal direction, circulating current between the batteries is prevented, resulting in excellent module characteristics. can get.

In the structure shown in FIGS. 1 and 2, the vertically adjacent batteries are connected in series to form strings, and the batteries installed at the ends of each string are connected in parallel to form a battery block. Are formed. If such a battery connection configuration is used, even if there is a temperature difference between the upper and lower batteries due to a temperature difference between the upper and lower batteries in the thermal insulation container, the batteries with the difference in resistance are connected in series to form a string. The resistance difference between the strings is not caused by the temperature difference in the vertical direction of the module. As a result, the problem that the circulating current flows in the battery block in which the strings are connected in parallel and the battery efficiency is reduced or a large current imbalance occurs between the strings is less likely to occur, and the efficiency and capacity of the module are high. There is. In this case, if a temperature distribution occurs in the lateral direction of the heat retaining container, a circulating current easily flows between the strings. Therefore, it is desirable to improve the heat insulation of the side surface of the heat retaining container to address this problem.

Further, as shown in FIGS. 4 and 5 and FIGS. 1 and 2, if the batteries are connected in series in the vertical direction, which tends to have a temperature distribution, the battery resistance becomes lower as the temperature becomes lower. Also, there is an advantage that the amount of heat generated by the battery due to energization increases, and as a result, the temperature distribution between the batteries becomes uniform.
A part or all of the vertically arranged batteries are connected in series to form a string, and a module is formed by a battery block in which all of the strings are connected in parallel. A similar effect can be obtained when a battery block is formed by connecting the battery blocks in parallel, and the battery blocks are connected in series or / and in parallel to form a module.

On the other hand, in FIG. 3, the batteries arranged in the horizontal direction are connected in series to form a string, and the batteries installed at the ends of the strings are connected in parallel in the vertical direction to form a battery block. Is formed. If such a battery connection configuration is used, even if the battery is damaged and sodium leaks from the battery and the upper and lower batteries are short-circuited, the voltages of the batteries arranged vertically in the module are almost equal. In addition, there is an advantage that the short-circuit current can be kept small, and the safety of the module is improved. A part or all of the batteries arranged in the horizontal direction are connected in series to form a string, and a string is formed by a battery block in which all of the strings are connected in parallel. The same effect can be obtained when battery blocks are formed by connecting the battery blocks in parallel, and the battery blocks are connected in series or / and in parallel to form a module.

As a specific example, as shown in FIGS. 1 and 2, a lock having a thickness of about 150 mm is provided inside a steel plate 1 having a width of 1.2 m, a depth of 0.9 m, a height of 1.8 m and a thickness of 2.3 mm. A heat insulating material 3 made of wool and an inner wall 2 made of a metal panel were further provided inside the insulating material 3, and a heater 8 composed of a sheathed heater was attached to the inner wall. In addition, a bottom plate 4, a pillar 6 and a shelf 7 are provided therein.
A measuring shelf having a width of 0.9 m and a depth of 0.6 m made of mica is installed, an insulating material 9 made of a mica plate is installed on a shelf 7, and a rated capacity of 2,000 Ah and an approximate size of 750 mm × 120
Forty mm-sodium-sulfur batteries were installed with their longitudinal direction set to be horizontal, and the batteries were connected in series with an aluminum bus bar 13 and the insulating particles 1 made of dry sand were placed in a container.
5 to make an approximately 150 kWh module.
The outer wall 1 and the bottom plate 4 are connected by bolts 5.

The obtained module has high fire resistance and is simpler in structure than the conventional structure in which the heat insulating container constituting the module is housed in a cubicle, so that it is suitable for cost reduction. The energy density of the module is about 75 kWh / cubic meter, which is almost the same as the energy density when a conventional heat-insulating container containing batteries is stored in a cubicle. Furthermore, even when the module was submerged, since the upper surface 11 and the side surface 12 of the outer wall 1 were air-tightly joined, excellent characteristics in terms of safety were obtained such that water did not enter inside at a high temperature.

[0068]

According to the present invention, the structure of the module is simplified, and the cost can be reduced. In addition, because of its excellent fire resistance and security against fire, it is possible to store and use modules in ordinary buildings, and to eliminate the need to provide open spaces around modules. Advantages can be obtained and the range of use of the module can be expanded.

According to the present invention, the height of the module can be reduced without lowering the energy density, the battery efficiency can be increased, and the module cost per unit output can be reduced. It is possible to realize a high-temperature sodium secondary battery module suitable for practical use, such as improving the degree of freedom in the height and area of the installation space and achieving both low cost and high efficiency.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a structure of a high-temperature sodium secondary battery module according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a front sectional view showing a structure of a high-temperature sodium secondary battery module according to another embodiment of the present invention.

FIG. 4 is a front sectional view showing a structure of a high-temperature sodium secondary battery module according to still another embodiment of the present invention.

FIG. 5 is a front sectional view showing a structure of a high-temperature sodium secondary battery module according to still another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 outer wall 3 heat insulating material 6 pillar 7 shelf 10 high-temperature sodium secondary battery 11 upper surface of outer wall 12 side surface of outer wall 13 bus bar 30 heat insulating container 31 space inside outer wall

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Manabu Gakudo 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Nuclear Power Division, Hitachi, Ltd. 1-1 1-1, Hitachi, Ltd. Nuclear Power Division, Hitachi, Ltd. Hitachi Engineering Co., Ltd. 3-2-1 Sachimachi, Hitachi F-term (reference) 5H011 AA04 AA06 AA09 AA13 BB03 CC06 DD11 KK01 5H022 AA14 AA19 CC25 CC30 KK04 5H029 AJ12 AJ14 AK05 AL13 AM15 BJ02 HJ05 DJ HJ12

Claims (15)

[Claims] 1. A high-temperature sodium secondary battery module in which a plurality of high-temperature sodium secondary batteries are electrically connected and housed inside a heat insulating container, wherein the outer wall of the heat insulating container constituting the module is made of a steel plate or a SUS plate, Its thickness is 1.
A high-temperature sodium secondary battery module, which is within a range of 6 mm to 10.0 mm. 2. The high-temperature sodium secondary battery module according to claim 1, wherein said outer wall has a thickness of not less than 2.3 mm. 3. The high-temperature sodium secondary battery module according to claim 1, wherein a heat insulating material is filled inside the outer wall, or a space inside the outer wall is evacuated or depressurized. A high-temperature sodium secondary battery module, wherein the high-temperature sodium secondary battery accommodated therein is kept warm. 4. The high-temperature sodium secondary battery module according to claim 1, wherein the upper surface and the side surface of the outer wall are hermetically sealed. 5. The high-temperature sodium secondary battery module according to claim 1, wherein the high-temperature sodium secondary battery is stored with the longitudinal direction thereof laid horizontally or obliquely. Secondary battery module. 6. The high-temperature sodium secondary battery according to claim 1, wherein a plurality of said high-temperature sodium secondary batteries are vertically stacked and housed. Next battery module. 7. The high-temperature sodium secondary battery module according to claim 6, wherein a pillar and a shelf are provided in the module.
A high-temperature sodium secondary battery module, wherein the high-temperature sodium secondary battery is supported by the columns and shelves. 8. The high-temperature sodium secondary battery module according to claim 1, wherein a side surface of the high-temperature sodium secondary battery has a rectangular parallelepiped shape. 9. The high-temperature sodium secondary battery module according to claim 1, wherein all the batteries housed in the module are connected in series. 10. The high-temperature sodium secondary battery module according to claim 6, wherein the vertically arranged batteries in the module are connected in series to form a string, and the batteries located at the end of the string are connected in parallel. A high-temperature sodium secondary battery module, which is connected to form a battery block. 11. The high-temperature sodium secondary battery module according to claim 6, wherein a string is formed by serially connecting the batteries arranged in the module in a lateral direction, and the batteries located at the ends of the string are connected in parallel. A high-temperature sodium secondary battery module, which is connected to form a battery block. 12. A high-temperature sodium secondary battery module according to claim 10, wherein said battery blocks are connected in series or / and in parallel. 13. A high-temperature sodium secondary battery module in which a plurality of high-temperature sodium secondary batteries are laid horizontally or obliquely and connected in series or in parallel with series connection and stored in the module. A high-temperature sodium secondary battery module, wherein a plurality of high-temperature sodium secondary batteries have their longitudinal ends alternately arranged in opposite directions to electrically connect the positive and negative electrodes of adjacent batteries. 14. A high-temperature sodium secondary battery module in which a plurality of high-temperature sodium secondary batteries are laid down horizontally or obliquely and housed in a module, wherein the side surfaces of the high-temperature sodium secondary battery have a rectangular parallelepiped shape. A high-temperature sodium secondary battery module characterized by the above-mentioned. 15. The high-temperature sodium secondary battery module according to claim 14, wherein a plurality of said high-temperature sodium secondary batteries are vertically stacked and housed.